Operational efficiency in a gas turbine engine generally increases as the temperature of the combustion stream increases. Higher combustion stream temperatures, however, may result in the production of high levels of nitrogen oxides (NOx) and other types of undesirable emissions. Such emissions may be subject to both federal and state regulations in the United States and also may be subject to similar regulations abroad. Moreover, financing of gas turbine engines and power plants often may be subject to international emissions standards. A balancing act thus exists between operating a gas turbine engine within an efficient temperature range while also ensuring that the output of nitrogen oxides and other types of regulated emissions remain well below mandated levels. Many other types of operational parameters also may be varied in providing such an optimized balance.
Operators of gas turbine engines and the like may prefer to use different types of fuels depending upon availability and price. For example, liquid fuels such as heavy fuel oil may be available. Heavy fuel oil, however, may have a high level of conversion to nitrogen oxides above certain temperatures. Specifically, liquid fuels such as heavy fuel oil may be high in fuel bound nitrogen. As a result, such fuels may need the use of selective catalytic reduction and the like to reduce the level of emissions. Such processes, however, add to the overall operating costs and the overall complexity of the gas turbine engine.
There is thus a desire for a combustor capable of efficiently combusting various fuels including liquid fuels high in fuel bound nitrogen such as heavy fuel oil and the like. Preferably, such a combustor may combust such fuels at lower temperatures to maintain overall emissions compliance.